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Comment: Re:How is this anywhere near profitable? (Score 1) 317

by rpstrong (#49623519) Attached to: Tesla's Household Battery: Costs, Prices, and Tradeoffs

My understanding is that Li Ion batteries have a lifetime of 1000 full charge cycles or roughly the proportional number of partial cycles.

Your understanding is off - partial cycles are not at all proportional to full cycles. Tesla limits both the discharge and charge levels in order to minimize battery damage. These are guaranteed for 10 years - potentially over 3,500 daily cycles for the 7KW model.

This means paying 3000 USD for 1000 cycles of 7 KWh, 43 cents per KWh. Why is this interesting for storing electricity other than possibly for emergencies where the cost may be less important?

It could be interesting if you have tiered pricing.

And if one is truly concerned about emergencies, why not buy an electric generator at a fraction of the cost and keep a 20 liter can of gas at 10 KWh per liter?

I'm looking at two use cases in my extended family.

My sister-in-law is building a small ranch for two horses on a chunk of land that is conveniently located, but which has no utilities. Solar power should suffice, and becomes very cost competitive when compared to the expense of installing a meter. The 7 Kw unit should be enough for her modest overnight needs.

Meanwhile, her mother - who is recovering from a stroke - lives alone. She does have a generator, but someone has to plug in the extension cords and start it up. The 10 Kw unit would keep her powered up through a brief blackout (not uncommon here) with no intervention required. (If the outage is longer, the generator is still an option.)

Recent research has tended to show that the Abominable No-Man is being replaced by the Prohibitive Procrastinator. -- C.N. Parkinson